Type 2 Diabetes Mellitus (T2DM) is a serious health problem that has increased dramatically worldwide due to the high and increasing prevalence of obesity. Medical management of T2DM is of limited success. Because not well controlled T2DM patients are in high risk of blindness, cardiovascular accident and end staged disease, T2DM has become a major health burden for society. Recent data on the relative effectiveness of gastrointestinal metabolic surgery played as bariatric surgery in the remission of T2DM, suggests that it may be significantly more effective than current medical treatment. In considering that less than half of the T2DM patients can achieve satisfactory treatment goal under current medical treatment, gastrointestinal metabolic surgery shall play an important role in T2DM treatment in the future. However, the indication for metabolic surgery and clinical predictors of success are not clear now. These clinical predictors can help us to choose appropriate not-well controlled T2DM patients to receive metabolic surgery and reduce dverse health outcomes in those patients.